Daily

This is the sample code for my talk at Elixir Conf EU 2022.

This demo is about setting up a Phoenix application with:

• Structured Logging
• Prometheus Metrics
• Opentelemetry Tracing

This also sets up a Docker Compose environment with:

• Grafana for dashboards
• Loki for logs
• Prometheus for metrics
• Tempo for tracing
• Locust for generating load
• Caddy as a reverse proxy and as a mocked API

Running

To have Loki working correctly inside Docker Compose, we first need to install the Loki Docker Driver:

docker plugin install grafana/loki-docker-driver:latest --alias loki --grant-all-permissions

Than you can start Docker Compose with:

docker-compose up -d

After everythign starts properly (it can take a while to download all the images and initialize everything), you should be able to go to http://localhost:4002/api/reports/daily and receive something like

{
  "task_descriptions": [
    "Eat",
    "Sleep",
    "Prepare ElixirConf EU 2022 Slides",
    "Repeat"
  ],
  "weather": "rainy"
}

Here are all the relevant ports the system will bring up

Port	Title	Links and other Info
3000	Grafana	Grafana Dashboard (admin/admin)
4001	Daily (Phoenix Server)	Useful if the gateway is not working for any reason
4002	Gateway (Caddy)	Will proxy to Daily. List Tasks, Daily Report
5000	Weather Mock (Caddy)	Returns always rainy. Get Weather
5100	Load Test (Locust)	Useful to generate synthetic load. Locust

Further Reading

Structured logging in Elixir using Loki by Alex Koutmos